Treatment of oil well production



May 10, 1966 0. w. GRAHAM 3,250,685

TREATMENT OF OIL WELL PRODUCTION Original Filed Dec. 5, 1960 P/LO T 25GAS SUPPLY CHEM/CAL M/XE/Z j WELL SZZEAM war 01L \7 STORAGE I 0/? 6,45supp y REC/RCULATED FUEL GAS SUPPLY 23 22 INVENTOR.

OLL/E WG/ZAHAM Y m1 AT TORNEY United States Patent O TREATMENT OF OILWELL PRODUCTION Ollie W. Graham, Tulsa, Okla, assignor to National TankCompany, Tulsa, Okla., a corporation of Nevada Continuation ofapplication Ser. No. 73,826, Dec. 5, 1960. This application July 2,1965, Ser. No. 477,062 Claims. (Cl. 196-132) This application is acontinuation of applicaton Serial No. 73,826, filed December 5, 1960.

The present invention relates to the operation of a treater for oil wellproduction. More specifically, the invention relates to controlling thefiring rate of a treater and feed rate of auxiliary chemicals whichsupplement the heat in reducing the water content of oil produced fromthe treater.

The basic sediment and water content of oil processed in the field hasbeen sensed by circuits built in accordance With Gunst US. Patent2,720,624, issued October 11, 1955. The primary element of this circuitis the equivalent of an electrical capacitance. The value of thecapacitance is a function of the dielectric constant of the oil in whichthe primary element is immersed.

The location of the capacitance element in any oilhandling system is acritical problem. If the oil is not dynamically flowed over thecapacitance probe, the BS&W will build up about the probe and cause theprobe to give a false signal to its circuit. If the pressure on the oilreduces as the oil flows over the probe, some of the oil will evolve asgas, changing the dielectric constant of the mixture in contact with theprobe independent of the BS&W content of the mixture.

In the present systems, when there is an increase in the water-cut ofthe produced oil, the oil is recirculated to the treater. The treaterhas its firing rate manually adjusted, and additional chemical may befed into the oil. These measures to increase efiiciency of the systemare fundamental. However, they are not carried out on an automatic andsystematic basis.

It is a primary object of the present invention to de: tect thedielectric constant of oil processed by a treater prior to pressurereduction on the processed oil.

Another object is to automatically isolate the produced oil from thepoint of delivery when its water content increases above a predeterminedpercentage and increase the firing rate of the treater.

Another object is to automatically isolate the produced oil from thepoint of delivery when the percentage of water in the oil increasesabove a predetermined percentage and increase the chemical rate added tothe process and/ or increase the firing rate from the treater.

The present invention contemplates a treater in which a capacitanceprobe is mounted in the clean oil collection chamber. The proberesponds, as a primary element, to the dielectric constant of the oiland any water not removed by the treater and prior to removal of the oilto the lower pressure of storage, or other processing equipment. Withthis arrangement, the dielectric constant of the oil is not caused tovary by gas breaking out of the liquid oil at the point of measurement.The index of dielectric constant then becomes a stable factor inindicating and/ or controlling the water content of oil processed by thetreater.

The invention further contemplates a system for automatically divertingthe produced oil to a special storage space, or simply recirculating theproduced oil through the treater, when the dielectric constant increasesa predetermined percentage. When the produced oil is diverted, thefiring of the treater is automatically increased a predetermined amount.It is further contemplated that ice by the control system including thecapacitance probe detecting the dielectric constant of the produced oil.

Other objects, advantages and features of this invention will becomeapparent to one skilled in the art upon consideration of the writtenspecifications, appended claims, and attached drawing wherein;

The treater The drawing illustrates a system in which a treater isarranged to 'field-processthe fluids of an oil well. The well stream isbrought to the system through conduit 1. Conduit 1 takes the well streaminto the shell of treater 2. The internal structure and conduits of thetreater are not shown in detail, for this might detract from thestructure in which the invention is embodied.

An upper separator section 3 is indicated within the upper portion ofthe treater shell by outlining separator bottom 4. The well streamfluids are introduced into this separator 3 and gaseous constituentsremove through conduit 5.

The remaining liquids of the well stream are taken to the lower portionof the treater shell. A direct-fired heater element 6 is shown, suppliedfuel gas through pipe 7. This fuel gas is normally regulated by valve 8which responds to the output of a first temperature responsive systemwith a primary element 9.

As clean oil is separated from the water of the well stream, it rises toa level 10. Level 10 is spaced a little below separator bottom 4. Thisclean oil is skimmed off through skimmer structure 11 and is droppeddown column 12. Column 12 could be in the form of a heatexchanger'bringing the incoming well stream of conduit 1 into heatexchange with the clean oil produced from the treater. For simplicity,column 12 is simply illus trated as a tank in which the clean oilcollects up to a level which will actuate discharge valve 13.Specifically, level controller 14 senses the level of clean oil incolumn 12 and actuates valve 13 to discharge the clean oil to the lowerpressure of conduit 15.

The water, separated from the oil, is disposed of by a conduit systemnot illustrated. Many features of such treater can be illustrated anddiscussed. However, the drawing here is developed to emphasize thatclean oil is collected in a body under the treater pressure which mayrange up to a few hundred pounds.

The problem Once clean oil is developed under pressure of this magnitude, and at temperatures ranging up to the neighborhood of F.,subsequent cooling and pressure reduction in conduit 15 will cause thelighter hydrocarbons to break from the liquid as vapor. This vapor willvary the dielectric constant of the mixture of gas and produced oili Ifa capacitance element, as a primary element, is made sensitive to thismixture, the resulting indication of basic sediment and watercontaminating the produced oil will be in error. The system will be apoor guide to the effec-' tiveness of the treating. Certainly the BS&Wmonitor system will be an unreliable device to control the treatingprocess in any manner.

Solution The present invention contemplates placing a capacitance probedirectly in the treater shell 2, certainly some where ahead of thepressure reduction which develops vapor from the processed hydrocarbons.Representative of this location, probe 20 is placed near the surface 10of the clean oil, but within the clean oil held under the treatingpressure which gives stability to the dielectric contact of the producedoil. The system responding to this probe Patented May 10, 1966 (Jontrolsystem generally Probe 20 is incorporated into the circuit ofmonitorcontroller 21. The circuit of 21 may take the form of thatillustrated in Gunst 2,720,624. The circuit disclosed there contemplatescontrol as a function of the circuit. Specifically, electric switchesmay be controlled by the circuit of 21, and the controlling circuitscontrolled by the switches are indicated. I

Various forces may be used to process the well stream of conduit 1. Theheat of burner 6 illustrates only one such force. Chemicals may also beused. These two forces are sufiicient to illustrate the variousprocessing forces that can be controlled to monitor the efiiciency ofthe system to produce merchantable oil for delivery to conduit 15 fromconduit 1. When the dielectric constant, sensed by probe 20, indicatesthe produced oil skimmed by 11 into column 12 has an undesirable amountof contaminating material in it, the monitor-controller 21 automaticallyand systematically diverts the oil delivered to conduit 15 to somedepository until the processing efficiency of the system has beenincreased.

To increase the efliciency of the treating system, the heat input israised. Also, the amount of chemical introduced into the well stream maybe increased. When the probe 20 indicates these measures have had thedesired effect of producing tmerchantable oil at surface 10, the outputof conduit 15 is again directed to the purchasing consumer.

Chemical injection Chemical injection is illustrated as carried out byan electric motor 22 driving pump 23. A circuit is indicated betweenmonitor-controller 21 and pump 23. The pump is regulated in any mannernecessary to vary the output of chemical pump 23, to chemical mixer 24,mountedin conduit 1. As probe 20 dictates, chemical introduced into thewell stream is regulated by this system.

Normal heating As previously indicated, valve 8 regulates fuel gas frompipe 7 to burner 6. Valve 8 is opened and closed by a fluid pressuredeveloped from a supply of gas in pipe 25. As illustrated, the fluidpressure of pipe 25 is applied beneath the diaphragm of valve 8 toovercome its spring force or is isolated from the diaphragm to allow thespring to operate the valve 8.

Isolation of gas valve 8 from pipe 25 and connection of gas valve 8 topipe 25 is accomplished with valve 26. This valve 26 is simply regulatedby the mechanical motion of bellows 27 which is part of a well-knownfluidfilled system including temperature responsive bulb 9.

The linkage between bellows 27 and valve 26 is adjusted so the valve 26will be seated, or raised from its seat, when the temperature to whichbulb 9 is exposed reaches a predetermined value. As an example, a normaltemperature of 150 F. may be desired at the position where bulb 9 ismounted. Therefore, fuel valve 8 is regulated, by this system, tomaintain the 150 F. temperature.

Any temperature in excess of 150 F. will close valve 8,

isolating burner 6 from this source of fuel gas.

Higher heating 4 i is applied to pipe 33. The fluid pressure is thenapplied to a by-pass valve 34 through a valve 35. Valve 35 is controlledby a temperature responsive bulb 36 'm the same manner bulb 9 controlsvalve 26.

The linkage between the system including bulb 36 and valve 35 is set soa temperature above the F. limit of bulb 9 will be maintained when bulb36 is efiective to control the firing of burner 6. Such highertemperature may be predetermined to be in the neighborhood of F.

The operation of the temperature system is simple and automatic. If theproduced oil develops a dielectric constant indicating a prohibitiveamount of water has shown up in the oil going to conduit 15,monitor-controller 21 applies the fluid pressure to open fuel valve 34.The temperature of 150 F., or above, on bulb 9 closes valve 8, but valve34 keeps open until the higher temperature of 180 F. is reached. Fuelvalve 8 is by-passed with pipe 37 and valve 34.

Diversion At the time monitor-controller 21 calls for the highertemperature to reduce the water content of the produced oil, it divertsthe oil of conduit 15 from conduit 38 to conduit 39. Thus, until thehigher heat input has cleaned the oil of its excess Water, the Wet oilis placed ina special storage Where it may be specially treated orrecirculated through the system.

To carry out the diversion, valve 40 is employed. Valve 40 is operatedby the same fluid pressure signal generated in pipe 33. Specifically,pipe 41 connects with the output of valve 32 to divert at the same timethe heat rate is increased.

From the foregoing it will be seen that this invention is one welladapted to attain all of the ends and objects hereinabove set forth,together with other advantages which are obvious and which are inherentto the method and apparatus. I

It will be understood that certain features and subcombinations are ofutility and may be employed without reference to other features andsubcombinations. This is contemplated by and is within the scope of theclaims.

As many possible embodiments may be made of the invention withoutdeparting from the scope thereof, it is to be understood that all matterherein set forth or shown in the accompanying drawings is to beinterpreted as illustrative and not in a limiting sense.

The invention having been described, what is claimed is:

1. A treating system for oil well production including,

a treater operating under pressure greater than atmospheric,

a source of heat mounted within the treater,

valve means connected in the outlet of the treater and through which theclean oil produced from the treater flows to a pressure lower thantreater pressure,

means connected to the treater and detecting the dielectric constant ofthe produced clean oil and located in the produced oil upstream of thevalve means and in proximity to the point of separation,

and control means connected to the source of heat connected to andadjustable by the detector for the dielectric constant to raise thefiring rate of the heat source when the dielectric constant of the oilchanges a predetermined amount.

2. A treating system for oil well production including,

a treater,

a source of heat mounted in the treater,

means connected to the treater and detecting the dielectric constant ofthe produced oil prior to discharge of the oil from treater pressure,

and a control means connected to the heat source and connected to andadjustable by thedetecting means for changing the output of the heatsource when the dielectric constant changes a predetermined amount.

3. A treating system for oil well production including,

a treater,

a source of heat mounted in the treater,

means connected to the treater and detecting the dielectric constant ofthe produced oil prior to discharge of the oil from treater pressure,

means arranged to inject chemical into the production before theproduction is heated by the heat source mounted in the treater,

and control means connected to the heat source and the chemicalinjecting means and connected to and adjustable by the detecting meansto change the output of the heat source and vary the rate of chemicalinjection when the dielectric constant changes a predetermined amount.

4. A treating system for oil well production including,

a treater,

a source of heat mounted in the treater,

means connected to the treater and detecting the dielectric constant ofthe produced oil prior to discharge of the oil from treater pressure,

means connected to the treater with which produced oil is recirculatedthrough the treater,

and a control means connected to the heat source and diverting means andconnected to and adjustable by the detecting means to change the outputof the heat source and divert the produced oil when the dielectricconstant changes a predetermined amount.

5. A treating system for oil Well production including,

a treater,

a source of heat mounted in the treater,

means connected to the treater and detecting the dielectric constant ofthe produced oil prior to discharge of the oil from treater pressure,

means connected to the treater With which produced oil is recirculatedthrough the treater,

and a control means connected to the diverting means and connected toand adjustable by the detecting means to divert the produced oil backthrough the treater when the dielectric constant changes a predeterminedamount.

References Cited by the Examiner UNITED STATES PATENTS 2,368,447 1/1945Buchan et a1 13788 X 2,654,067 9/1953 Bruce 324-61 2,720,624 10/1955Gunst et a1 324-61 2,773,556 12/1956 Meyers et a1 21096 X 2,942,689 6/1960 Walker et a1.

3,005,554 10/1961 Kuntz 32461 X 3,107,526 10/1963 Kuntz 324-61 X NORMANYUDKOFF, Primary Examiner.

F. E. DRUMMOND, Assistant Examiner.

1. A TREATING SYSTEM FOR OIL WELL PRODUCTION INCLUDING, A TREATEROPERATING UNDER PRESSURE GREATER THAN ATMOSPHERIC, A SOURCE OF HEATMOUNTED WITHIN THE TREATER, VALVE MEANS CONNECTED IN THE OUTLET OF THETREATER AND THROUGH WHICH THE CLEAN OIL PRODUCED FROM THE TREATER FLOWSTO A PRESSURE LOWER THAN TREATER PRESSURE, MEANS CONNECTED TO THETREATER AND DETECTING THE DIELECTRIC CONSTANT OF THE PRODUCED CLEAN OILAND LO-